/*
 * Copyright 2002-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Globalization;
using Spring.Util;

namespace Spring.Globalization.Formatters;

/// <summary>
/// Implementation of <see cref="IFormatter"/> that can be used to
/// format and parse numbers.
/// </summary>
/// <remarks>
/// <para>
/// <c>NumberFormatter</c> uses number-related properties of the
/// <see cref="NumberFormatInfo"/> to format and parse numbers.
/// </para>
/// <para>
/// This formatter works with both integer and decimal numbers and allows
/// you to format and parse numbers that conform to <see cref="NumberStyles.Number"/>
/// number style (leading and trailing white space and/or sign, thousands separator,
/// decimal point)
/// </para>
/// <para>
/// If you use one of the constructors that accept culture as a parameter
/// to create an instance of <c>NumberFormatter</c>, default <c>NumberFormatInfo</c>
/// for the specified culture will be used.
/// </para>
/// <para>
/// You can also use properties exposed by the <c>NumberFormatter</c> in order
/// to override some of the default number formatting parameters.
/// </para>
/// </remarks>
/// <author>Aleksandar Seovic</author>
public class NumberFormatter : IFormatter
{
    private NumberFormatInfo formatInfo;

    /// <summary>
    /// Initializes a new instance of the <see cref="NumberFormatter"/> class
    /// using default <see cref="NumberFormatInfo"/> for the current thread's culture.
    /// </summary>
    public NumberFormatter() : this(CultureInfo.CurrentCulture)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="NumberFormatter"/> class
    /// using default <see cref="NumberFormatInfo"/> for the specified culture.
    /// </summary>
    /// <param name="cultureName">The culture name.</param>
    public NumberFormatter(string cultureName) : this(CultureInfo.CreateSpecificCulture(cultureName))
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="NumberFormatter"/> class
    /// using default <see cref="NumberFormatInfo"/> for the specified culture.
    /// </summary>
    /// <param name="culture">The culture.</param>
    public NumberFormatter(CultureInfo culture)
    {
        formatInfo = culture.NumberFormat;
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="NumberFormatter"/> class
    /// using specified <see cref="NumberFormatInfo"/>.
    /// </summary>
    /// <param name="formatInfo">
    /// The <see cref="NumberFormatInfo"/> instance that defines how
    /// numbers are formatted and parsed.
    /// </param>
    public NumberFormatter(NumberFormatInfo formatInfo)
    {
        this.formatInfo = formatInfo;
    }

    /// <summary>
    /// Gets or sets the number of decimal digits.
    /// </summary>
    /// <value>The number of decimal digits.</value>
    /// <seealso cref="NumberFormatInfo.NumberDecimalDigits"/>
    public int DecimalDigits
    {
        get { return formatInfo.NumberDecimalDigits; }
        set { formatInfo.NumberDecimalDigits = value; }
    }

    /// <summary>
    /// Gets or sets the decimal separator.
    /// </summary>
    /// <value>The decimal separator.</value>
    /// <seealso cref="NumberFormatInfo.NumberDecimalSeparator"/>
    public string DecimalSeparator
    {
        get { return formatInfo.NumberDecimalSeparator; }
        set { formatInfo.NumberDecimalSeparator = value; }
    }

    /// <summary>
    /// Gets or sets the number group sizes.
    /// </summary>
    /// <value>The number group sizes.</value>
    /// <seealso cref="NumberFormatInfo.NumberGroupSizes"/>
    public int[] GroupSizes
    {
        get { return formatInfo.NumberGroupSizes; }
        set { formatInfo.NumberGroupSizes = value; }
    }

    /// <summary>
    /// Gets or sets the number group separator.
    /// </summary>
    /// <value>The number group separator.</value>
    /// <seealso cref="NumberFormatInfo.NumberGroupSeparator"/>
    public string GroupSeparator
    {
        get { return formatInfo.NumberGroupSeparator; }
        set { formatInfo.NumberGroupSeparator = value; }
    }

    /// <summary>
    /// Gets or sets the negative pattern.
    /// </summary>
    /// <value>The number negative pattern.</value>
    /// <seealso cref="NumberFormatInfo.NumberNegativePattern"/>
    public int NegativePattern
    {
        get { return formatInfo.NumberNegativePattern; }
        set { formatInfo.NumberNegativePattern = value; }
    }

    /// <summary>
    /// Formats the specified number value.
    /// </summary>
    /// <param name="value">The value to format.</param>
    /// <returns>Formatted number <paramref name="value"/>.</returns>
    /// <exception cref="ArgumentNullException">If <paramref name="value"/> is <c>null</c>.</exception>
    /// <exception cref="ArgumentException">If <paramref name="value"/> is not a number.</exception>
    public string Format(object value)
    {
        AssertUtils.ArgumentNotNull(value, "value");
        if (!NumberUtils.IsNumber(value))
        {
            throw new ArgumentException("NumberFormatter can only be used to format numbers.");
        }

        return String.Format(formatInfo, "{0:N}", value);
    }

    /// <summary>
    /// Parses the specified number value.
    /// </summary>
    /// <param name="value">The number value to parse.</param>
    /// <returns>Parsed number value as a <see cref="Double"/>.</returns>
    public object Parse(string value)
    {
        if (!StringUtils.HasText(value))
        {
            return 0d;
        }

        NumberStyles numberStyle = NumberStyles.Number;
        if (formatInfo.NumberNegativePattern == 0)
        {
            numberStyle |= NumberStyles.AllowParentheses;
        }

        return Double.Parse(value, numberStyle, formatInfo);
    }
}
